Improve Benchmarks

[Nerixyz]

This is some kind of meta issue. The goal is to improve the process of increasing Chatterino's performance and decreasing its resource usage. By having good benchmarks, identifying slow paths can become easier and the impact of different changes can be tracked.

• Compile (not run) benchmarks in CI
• Not really related to benchmarks but useful for new contributors: Document CMake options (as mentioned in Improve Benchmarks #4947 (comment), by adding more comments on option(..))
• Add benchmark for TwitchMessageBuilder
• Add benchmark for parsing of recent messages
• Add benchmark for message layout (not 100% sure if this can be done yet; this needs tests as well)
• Add benchmark for filters

Feel free to suggest more items.

[pajlada]

Not really related to benchmarks but useful for new contributors: Document CMake options

This should be documented by saying: "Open CMakeLists.txt and look at the top options", and potentially add better comments there.
If you are a new contributor looking to find out what options there are, you might as well know what a CMakeLists.txt file looks like